1. Field of the Invention
The present invention relates to devices utilized to prevent postoperative hip dislocations and recurrent traumatic hip dislocations. More particularly, this invention relates to a dynamic hip stabilizer with a combination of components that generate tensile forces capable of holding a patient's thigh with enough tension to control excessive adduction, flexion or extension, control excessive internal or external rotation, provide hip stability by controlling and modifying certain hip motions through increasing tension as the extremes of a particular motion are approached, and provide hip stability by constantly maintaining elevated abductor tension across the hip joint.
2. Description of the Related Art
There are a variety of techniques currently in use to prevent postoperative hip dislocations, recurrent traumatic hip dislocations, etc., some of which make use of specialized devices. A basic technique is to place a pillow between the thighs of the patient to cause abduction of the hips. A slightly more advanced technique is to secure a foam abduction pillow between the thighs with hook and loop straps to hold the hips in wide abduction. More advanced techniques include the use of single hip spica abduction braces, which generally comprise a thermoplastic waist brace attached to a thermoplastic thigh component by a hinged metal bar. The metal hinge portion allows flexion of the hip within a variable fixed range which can be set by the treatment provider. Single and bilateral hip spica casts, which serve to prevent all hip motions, also have long been used. Another type of device is the hip abduction brace, which generally comprises two curved semicircular plastic plates connected by hinges to a central threaded expansion-contraction device. By turning a central control threaded screw, the semicircular plastic plates spread out. When held between the proximal thighs by hook and loop straps, the device pushes the thighs apart, attempting to maintain abduction of the hips.
Various shortcomings are associated with the use of the above techniques and devices. Conventional pillows are too moveable and not wide enough to give consistent abduction, and undesirably allow the patient to move about. As a result, a pillow is rarely capable of preventing postoperative dislocation because it does not move with the patient who rolls over, or when the patient sits at the side of the bed or is being transferred to a wheel chair. Foam abduction pillows are clumsy and require considerable nursing effort to roll a patient from side to side. Furthermore, foam abduction pillows must be removed when the patient sits up and when bed-to-chair transfers are required.
A significant shortcoming of hip spica casts is the risk of prolonged stiffness because of the lack of all motion at the hip for many weeks. While single hip spica abduction braces avoid this concern, they require measurement and fitting by an orthotist and are formed from prefabricated parts of thermoplastic material and metal struts. Though single hip spica abduction braces can be worn in bed and while the patient sits and is being transferred, form-fit plastic abdominal and thigh portions of the brace often do not fit well, and allow many patients to rotate, putting the hip at risk. These braces also often allow some adduction and internal rotation, which is a significant risk to hip stability. Furthermore, this type of brace offers no compression of the femur against the pelvic acetabulum.
Hip abduction braces work reasonably well for the first days after surgery when the patient is fairly inactive. However, if not maintained in its fully abducted position, this type of brace allows for adduction to neutral and flexion is uncontrolled. The brace is removed for perineal care and when sitting the patient up at bedside. In addition, this type of brace cannot be worn during patient bed-to-wheelchair transfers or during gait training.
Other techniques and braces that pertain to the prevention of hip dislocations, or more generally to supporting or bracing the hip region, include U.S. Pat. No. 976,564 to Goodson, U.S. Pat. No. 1,722,192 to Brokaw, U.S. Pat. No. 2,332,119 Springer, U.S. Pat. No. 4,531,515 to Rolfes, U.S. Pat. No. 4,709,692 to Kirschenberg et al., U.S. Pat. No. 4,901,710 to Meyer, U.S. Pat. No. 4,905,678 to Cumins et al., U.S. Pat. No. 4,926,845 to Harris, U.S. Pat. No. 5,267,928 to Barile et al., U.S. Pat. No. 5,286,251 to Thompson et al., U.S. Pat. No. 5,465,428 to Earl, U.S. Pat. No. 5,840,050 to Lerman, U.S. Pat. No. 5,893,367 to Dubats et al., U.S. Pat. No. 5,928,175 to Tanaka, and U.S. Pat. No. 6,039,707 to Crawford et al. Each of Goodson, Brokaw, Barile et al. and Earl entail device with a waist portion, thigh portions, and elastic straps that interconnect the waist and thigh portions. Goodson's straps are limited to the posterior to provide posture support. Brokaw discloses a brace with inelastic anterior straps and elastic posterior straps. Barile et al. disclose a one-piece support garment with elastic anterior and posterior straps and elastic lateral straps, the latter of which may be wrapped in various ways around the thighs or hips of the wearer. Finally, Earl discloses an exercise device whose elastic straps are limited to the posterior side of the device.
It would be desirable if an improved device was available that was specifically configured to prevent hip dislocations by controlling excessive adduction, flexion and/or extension, controlling excessive internal or external rotation, increasing hip stability.